“Being a toxic fan is when you’re insulting and berating and harassing the people making the movies or the people that like them.”
I think it would be sensible to add “in the context of this thread”. There’s more to toxicity than what you’re suggesting, and while it’s your prerogotive to frame the discussion of this thread, I think it is rather odd to lay claim to a term in this manner. Toxic fandom is a term, that describes certain behaviours by fans in general, it isn’t limited to a specific group anymore than racism is limited to white men. Now, it is possible to limit a discussion to the racist expressions of white men, but to then rigourously define racism as insulting or berating non-white people, justly invites criticism, as your definition of toxic fandom does by me.
I also think, that if you are going to limit the scope of the discussion, it should be done in a consistent manner, and so we’re on a slippery slope when we applaud a video that conflates insulting and berating a work of art with harassing the people making the movies or the people that like them. Expressing a strong negative opinion on a work of art, no matter how unreasonable that opinion seems to be, does not automatically equate to toxicity. The fact that the creator of the video not just addresses the toxic elements in the fandom, but also attempts to frame these extremes as evidence, that many of the criticisms leveled at the work in question are invalid, makes the video suspect in my view.